KR100302975B1 - Discharge vanes for axial fans - Google Patents

Abstract

The fan housing of the axial fan having a flow resistor such as a coil or grill in closely spaced relation is provided with a plurality of vanes extending radially and spaced circumferentially on the discharge side. The vanes serve as radial diffusers in cooperating with rotational / irregular flow in the fan orifice to guide the flow radially and to distribute it onto the front of the flow resistor.

Description

Discharge vane for axial fan {DISCHARGE VANES FOR AXIAL FANS}

Conventional axial fans, such as propeller fans, generally have fan housings that completely or partially surround the fan blade tips. Such fans are generally used for HVAC applications such as condensation units. In this application, the fan basically blows air through a flow resistor, such as a condenser coil. When such a fan is used on the condenser side of an air conditioning system, the fan is typically associated with a condensate slinger structure such that the collected condensate is sprayed into the fan flow or onto the condenser coil. A problem associated with axial fans with conventional housings is that rotational / irregular flow in the area enclosed by the housing and the coil creates noise by interacting with the blade tip; Turbulent flow leaks into the blade passages to produce noise; Turbulent / rotating flows cause air to be inefficiently distributed to the coil.

Radial vanes are provided on the discharge side of the fan housing of the axial fan. The blades of the fan may be wrapped by shrouds or have free tips. The radial vanes are disposed radially outward of the blade tip and preferably extend over the depth of the blade and extend at least a short distance past the blade. The radial vanes serve as radial diffusers, which distribute the rotational flow so that less turbulent flow interacts with the blade tip, thereby reducing the blade passage noise and thus improving fan performance. Moreover, the vanes aid in the distribution of condensate onto the condenser coils.

It is an object of the present invention to reduce blade passage noise in an axial fan.

Another object of the invention is to facilitate the distribution of condensate onto the condenser coil.

It is a further object of the present invention to improve air distribution and fan performance in the fan coil unit. These and other objects will be apparent from the following and are attained by the present invention.

1 is a partially cutaway sectional view of a room air conditioner employing the present invention.

FIG. 2 is a side view of the discharge side of the fan housing of FIG. 1; FIG.

3 is a graph of A-weighted sound power level (dBA) versus frequency (Hz) for an axial fan blown through a heat exchanger and wrapped by a shroud, with and without radial vanes. .

4 is a side view of the discharge side of the first change fan housing;

5 is a side view of the discharge side of the second modified fan housing;

<Explanation of symbols for the main parts of the drawings>

12: housing

20: evaporator

26: axis

28: motor

30: condenser

32: fan housing

32-1: entrance opening

32-a to 32-n, 132-a to 132-n, 232-a to 232-n: vane

34: axial fan

34-1: Blade

Basically, the air flow from the axial fan with the flow resistor on the downstream side is such that the condensate entrained in the flow reduces the blade passage noise by dispersing the rotating flow interacting with the fan blade tip. It is guided by circumferentially spaced radial guide vanes that serve as radial diffusers so as to be distributed on the condenser coil.

In Fig. 1, reference numeral 10 generally denotes a room air conditioner employing the present invention. Typically, the room air conditioner 10 has a housing 12 that can be placed in a window or through a wall sleeve. The air conditioning housing 12 is divided into an evaporator or an interior part and a condenser or an outdoor part by a partition or barrier 14, and each part is divided into an intake part and an outlet part with respect to a fan disposed therein. The housing 12 includes an inlet grill 12-1 facing the room to be cooled when the air conditioner 10 is installed. The evaporator 20 is disposed just behind the inlet grill 12-1 and mounted in the evaporator shroud or housing 22. The housing 22 has a central rear opening that connects to the inlet of the evaporator fan 24. The fan 24 is driven by the motor 28 through the shaft 26 which penetrates the partition 14 and is sealed and supported by the partition 14. Evaporator fan 24 discharges air through a louver (not shown) to the room to be cooled. The condenser 30 is disposed in the housing 12 and the discharge side of the condenser faces the outdoors. The condenser fan housing 32 is connected to the inside of the condenser 30 and the housing 12 so that a fan chamber 33 containing at least a portion of the moving part of the condenser fan 34 is formed. The fan housing 32 includes an inlet orifice 32-1. The fan 34 is axial propeller type and is shown as being completely disposed in the fan chamber 33 and is connected to the motor 28 via the shaft 26 such that the two fans 24, 34 are driven together. have. The fan 34 has a blade 34-1 and a shroud 34-2. A portion of the fan 34 may extend into the orifice 32-1.

During operation, motor 28 drives evaporator fan 24 and condenser fan 34 together. The evaporator fan 24 sucks air from the room to be cooled, and the air passes through the inlet grill 12-1, the evaporator 20 for cooling the air, and the fan 24 in succession to a louver (not shown). Pass back to the room. The condenser fan 34 sucks outside air into the housing 12 through an inlet grill (not shown), and the air passes continuously through the fan 34 and the condenser 30 to remove heat from the condenser. I'm going.

The above-described structure and operation are generally conventional, with the flow leaving the condenser fan 34 tending to rotate / irregular, resulting in inefficient distribution of air and droplet entrained condensate onto the condenser 30 coil. The present invention further includes radial vanes 32-a, 32-b,... 32-n with various radial extents increasing in the downstream direction as best seen in FIG. 3. As best shown in Figure 2, the vanes 32-a through 32-n are circumferentially spaced around the inlet orifice 32-1. The inlet orifice 32-1 is disposed on the suction side of the fan housing 32 but does not center in the fan housing 32 due to the need to place other components within the housing 12. Thus, the inlet orifice 32-1 and the fan 34 do not center in the condenser 30 coil. Since there is no vane or the length of the vanes is reduced, the height of the room air conditioner 10 can be reduced, so that the spacing of the vanes 32-a to 32-n is even at least on the top and bottom of the fan housing 32. Not. The vanes 32-a to 32-n are at least partially coextensive in the axial direction with the blade 34-1 of the fan 34 and extend radially outwardly of the fan housing 32. . The vanes 32-a through 32-n are not symmetric and have varying lengths. The vanes 32-a to 32-n have a gentle S-shape and preferably extend axially by a short distance past the downstream side of the blade 34-1 of the fan 34.

The downstream resistance caused by the coil of condenser 30 tends to provide radial component discharge to the fan 34 with the rotational flow overlapping. The vanes 32-a to 32-n cooperate with the flow of radial components to remove the rotating component and direct the radial components of the flow to the outer circumference of the coil of the condenser 30 so that the air and splash entrained condensate are further It evenly distributes onto the condenser coil and reduces blade passage noise.

Referring now to FIG. 3, the graph shows the acoustics of adding vanes 32-a to 32-n to the shroud of an axial fan blowing through a heat exchanger / condenser at 1/3 octave sound power level. Effect. The discharge flow rate was 0.198 m ³ / s (420 cfm) at a motor speed of 1400 rpm. Noise was reduced from 64.2 dBA to 63.8 dBA when the vanes 32-a through 32-n were added to the shroud as a whole. However, it will be appreciated that the maximum reduction region was 125 Hz to 225 Hz.

Referring now to FIG. 4, the fan housing 132 is different from the fan housing 32 because the radial vanes 132-a through 132-n are straight rather than S-shaped. The vanes 132-a through 132-n cooperate with the flow to direct the flow onto the front of the condenser coil.

Referring now to FIG. 5, fan housing 232 is different from fan housings 32 and 132 because radial vanes 232-a through 232-n are in the shape of aircraft wings. The vanes 232-a through 232-n cooperate with the flow to direct the flow onto the front of the condenser coil.

It will be appreciated that all embodiments of the invention operate in basically the same way. The vanes cooperate with the rotating component of the radial flow to guide the flow radially and to the front of the condenser coil. The vanes may have even or varying spacing and may have any shape to effect low loss guidance of fluid flow.

While the preferred embodiments of the present invention have been shown and described, those skilled in the art can make other changes. For example, the present invention can be used where downstream losses or resistance occur in the grill rather than in the coil. Accordingly, the scope of the invention should only be limited by the appended claims.

The radial vanes disposed within the fan housing of the present invention serve as a radial diffuser and disperse the rotational flow, thereby reducing the blade passage noise as less turbulent flow interacts with the blade tip, thereby improving fan performance and also condenser Helps distribute the condensate onto the coil.

Claims (5)

In a fan housing, Suction side and discharge side, An inlet orifice disposed in the fan housing; A shroud axial fan having at least partially inserted into the fan housing through the inlet orifice and having a plurality of blades; A plurality of radially spaced apart circumferentially spaced radially spaced from the fan, disposed in the fan housing on the discharge side of the inlet orifice, at least a portion of the fan housing being axially spaced and radially spaced with the same boundaries as the blades in the axial direction; With vanes, A flow resistor disposed downstream of said axial fan and vanes axially spaced from said axial fan and vanes, And the fan housing is radially spaced apart from the blade by a distance that increases in the downstream direction such that the vanes increase in their radial width in the downstream direction. The fan housing of claim 1 wherein said vanes are asymmetrical. The fan housing of claim 1, wherein the vanes are straight. The fan housing of claim 1 wherein the vanes are in the shape of an aircraft wing. The fan housing of claim 1, wherein the vane extends to a periphery of the fan housing.